strength of the wind, was borne
to the earth again and again, rebounding high in air after each impact,
until freedom was gained only by the sacrifice of a portion of the rope.

Wise recommends a pendant line of 600 or 800 feet, capable of bearing a
strain of 100 lbs., and with characteristic ingenuity suggests a special
use which can be made of it, namely, that of having light ribbons tied
on at every hundred feet, by means of which the drifts of lower currents
may be detected. In this suggestion there is, indeed, a great deal of
sound sense; for there is, as will be shown hereafter, very much value
to be attached to a knowledge of those air rivers that are flowing,
often wholly unsuspected, at various heights. Small parachutes, crumpled
paper, and other such-like bodies as are commonly thrown out and relied
on to declare the lower drifts, are not wholly trustworthy, for this
reason--that air-streams are often very slender, mere filaments, as
they are sometimes called, and these, though setting in some definite
direction, and capable of entrapping and wafting away some small body
which may come within their influence, may not affect the travel of so
big an object as a balloon, which can only partake of some more general
air movement.

Wise, by his expedient of tying ribbons at different points to his trail
rope, would obtain much more correct and constant information respecting
those general streams through which the pendant rope was moving. A
similar expedient adopted by the same ingenious aeronaut is worthy
of imitation, namely, that of tying ribbons on to a rod projecting
laterally from the car. These form a handy and constant telltale as to
the flight of the balloon, for should they be fluttering upwards the sky
sailor at once knows that his craft is descending, and that he must act
accordingly.

The material, pure silk, which was universally adopted up to and after
the period we are now regarding, is not on every account to be reckoned
the most desirable. In the first place, its cost alone is prohibitive,
and next, although lighter than any kind of linen, strength for
strength, it requires a greater weight of varnish, which, moreover,
it does not take so kindly as does fabric made of vegetable tissue.
Further, paradoxical as it may appear, its great strength is not entirely
an advantage. There are occasions which must come into the experience of
every zealous aeronaut when his balloon has descended in a rough wi